Steady-state ab-initio laser theory for lasers with fully or nearly degenerate resonator modes

TL;DR

This paper extends the steady-state ab-initio laser theory (SALT) to effectively describe lasers with degenerate or nearly degenerate resonator modes, broadening its applicability to more complex laser systems.

Contribution

The authors develop a method to apply SALT to lasers with degenerate modes by combining it with linear stability analysis, enabling stable single-mode solutions in such cases.

Findings

SALT can be extended to degenerate mode lasers.

The method successfully describes 1D ring and 2D microdisk lasers.

Stable single-mode solutions are obtained for degenerate modes.

Abstract

We investigate the range of validity of the recently developed steady-state ab-initio laser theory (SALT). While very efficient in describing various microlasers, SALT is conventionally believed not to be applicable to lasers featuring fully or nearly degenerate pairs of resonator modes above the lasing threshold. Here we demonstrate how SALT can indeed be extended to describe such cases as well, with the effect that we significantly broaden the theory's scope. In particular, we show how to use SALT in conjunction with a linear stability analysis to obtain stable single-mode lasing solutions that involve a degenerate mode pair. Our flexible and efficient approach is tested on one-dimensional ring lasers as well as on two-dimensional microdisk lasers with broken symmetry.